C208 pilot reported smoke in the cockpit on a rainy night.

Attributes
ACN	1522959
Time
Date	201802
Local Time Of Day	1801-2400
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Light	Night
Aircraft 1
Make Model Name	Caravan 208B
Operating Under FAR Part	Part 135
Flight Phase	Descent
Route In Use	Vectors
Flight Plan	IFR
Component
Aircraft Component	Autopilot
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Commercial Flight Crew Instrument Flight Crew Flight Instructor
Experience	Flight Crew Last 90 Days 192 Flight Crew Total 8300 Flight Crew Type 1856
Events
Anomaly	Aircraft Equipment Problem Critical

Narrative:

During a rainy night I was on downwind at 4;000 ft when the auto pilot quit working. After the ap (autopilot) quit working I noticed the smoke coming in the cockpit. I immediately [advised ATC]. I pulled the ap circuit breaker and monitored the situation while being vectored to the ILS. After intercepting the localizer I noticed the smoked stopped. I told both approach and tower the smoked had stopped. After landing safely I stopped and talked with ground and the fire trucks to secure the [aircraft]. I then explained that I felt I could taxi. [Ground] cleared me to taxi and the fire trucks followed. I then shut the airplane down and got out the cockpit to allow maintenance and the fire crew to check out the plane.

Original NASA ASRS Text

Title: C208 pilot reported smoke in the cockpit on a rainy night.

Narrative: During a rainy night I was on downwind at 4;000 ft when the auto pilot quit working. After the AP (Autopilot) quit working I noticed the smoke coming in the cockpit. I immediately [advised ATC]. I pulled the AP circuit breaker and monitored the situation while being vectored to the ILS. After intercepting the localizer I noticed the smoked stopped. I told both approach and tower the smoked had stopped. After landing safely I stopped and talked with Ground and the Fire Trucks to secure the [aircraft]. I then explained that I felt I could taxi. [Ground] cleared me to taxi and the fire trucks followed. I then shut the airplane down and got out the cockpit to allow maintenance and the fire crew to check out the plane.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.